1,906 research outputs found

    Food Antimicrobials Nanocarriers

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    Natural food antimicrobials are bioactive compounds that inhibit the growth of microorganisms involved in food spoilage or food-borne illness. However, stability issues result in degradation and loss of antimicrobial activity. Nanoencapsulation allows protection of antimicrobial food agents from unfavorable environmental conditions and incompatibilities. Encapsulation of food antimicrobials control delivery increasing the concentration of the antimicrobials in specific areas and the improvement of passive cellular absorption mechanisms resulted in higher antimicrobial activity. This paper reviews the present state of the art of the nanostructures used as food antimicrobial carriers including nanoemulsions, nanoliposomes, nanoparticles, and nanofibers

    Phase diagram of Fe-doped Ni-Mn-Ga ferromagnetic shape-memory alloys

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    We have studied the effect of Fe addition on the structural and magnetic transitions in the magnetic shape memory alloy Ni-Mn-Ga by substituting systematically each atomic species by Fe. Calorimetric and AC susceptibility measurements have been carried out in order to study the magnetic and structural transformation properties. We find that the addition of Fe modifies the structural and magnetic transformation temperatures. Magnetic transition temperatures are displaced to higher values when Fe is substituted into Ni-Mn-Ga, while martensitic and premartensitic transformation temperatures shift to lower values. Moreover, it has been found that the electron per atom concentration essentially governs the phase stability in the quaternary system. However, the observed scaling of transition temperatures with e/ae/a differs from that reported in the related ternary system Ni-Mn-Ga.Comment: 8 pages, 8 figures. Accepted for publication in the Physical Review

    Inoculation of the Leishmania infantum HSP70-II null mutant induces long-term protection against L. amazonensis infection in BALB/c mice

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    Leishmania amazonensis parasites are etiological agents of cutaneous leishmaniasis in the New World. BALB/c mice are highly susceptible to L. amazonensis challenge due to their inability to mount parasite-dependent IFN-γ-mediated responses. Here, we analyzed the capacity of a single administration of the LiΔHSP70-II genetically-modified attenuated L. infantum line in preventing cutaneous leishmaniasis in mice challenged with L. amazonensis virulent parasites. In previous studies, this live attenuated vaccine has demonstrated to induce long-protection against murine leishmaniasis due to Old World Leishmania species. Vaccinated mice showed a reduction in the disease evolution due to L. amazonensis challenge, namely reduction in cutaneous lesions and parasite burdens. In contrast to control animals, after the challenge, protected mice showed anti-Leishmania IgG2a circulating antibodies accompanied to the induction of Leishmania-driven specific IFN-γ systemic response. An analysis performed in the lymph node draining the site of infection revealed an increase of the parasite-specific IFN-ϒ production by CD4+ and CD8+ T cells and a decrease in the secretion of IL-10 against leishmanial antigens. Since the immunity caused by the inoculation of this live vaccine generates protection against different forms of murine leishmaniasis, we postulate LiΔHSP70-II as a candidate for the development of human vaccines.This research was funded by grants from Ministerio de Ciencia e Innovación FISPI11/00095 and FISPI14/00366 (FEDER FUNDING) to M.S. and RYC-2016-19463 and RTI2018-343 to S.I. J.M.R. and M.S. are funded by the Fondo de Investigaciones Sanitarias (ISCIII-RETICRD16/0027/008-FEDER). E.H.G. is supported by a FPI grant from the Spanish Ministerio de Ciencia e Innovación. Institutional grants from the Fundación Ramón Areces and Banco de Santander to the CBMSO are also acknowledged. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewe

    Optical ladder operators in the Glauber-Fock oscillator array

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    In this study, we investigate the stationary states of the Glauber-Fock oscillator waveguide array. We begin by transforming the associated Hamiltonian into the form of a quantum harmonic oscillator Hamiltonian, allowing the implementation of a supersymmetric (SUSY) approach. By considering the simplest case for the intertwining operator, the optical ladder operators are straightforwardly constructed and shown to map eigensolutions into eigensolutions of the corresponding Hamiltonian operator, in pretty much the same manner as it is done for the quantum harmonic oscillator case. The ladder of the corresponding (eigen) supermodes is then easily established

    Exact Solution to the Driven Jaynes-Cummings System

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    We investigate the dynamics of the driven Jaynes-Cummings model, where a two-level atom interacts with a quantized field and both, atom and field, are driven by an external classical field. Via an invariant approach, we are able to transform the corresponding Hamiltonian into the one of the standard Jaynes-Cummings model. Subsequently, the exact analytical solution of the Schr\"odinger equation for the driven system is obtained and employed to analyze some of its dynamical variables.Comment: 7 pages, 5 figure

    Impact exercise strategies in the HRQOL of the sedentary adults

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    El objetivo del estudio fue analizar la eficacia de diferentes estrategias de intervención del ejercicio físico y relacionarlas con la percepción de la calidad de vida relacionada con la salud (CVRS) en adultos mayores sedentarios. Participaron 100 sujetos, con edades comprendidas entre los 60 y 70 años, que fueron divididos aleatoriamente en cuatro grupos: control, recomendación, prescripción y monitorización. La intervención de ejercicio físico tuvo una duración de 6 meses. Para la valoración de la CVRS se utilizó el cuestionario SF-36. Los grupos monitorización y prescripción obtuvieron los mayores valores en todos los dominios en el análisis intragrupos. La función física y la salud general y mental obtienen los mayores valores significativos entre grupos (p<.05). Entre los grupos prescripción y monitorización no existen diferencias significativas en ninguna dimensión. Sin embargo el grupo de monitorización obtuvo valores superiores en salud mental, no siendo así en salud físicaThe aim of the study was to analyze the effectiveness of different intervention strategies of exercise and relate the perception of quality of life related to health (HRQOL) in sedentary older adults. It involved 100 subjects, aged between 60 and 70, who were randomly divided into four groups: control, recommend, prescribe and monitor. The exercise intervention lasted 6 months. The SF-36 questionnaire was used for the assessment of HRQOL. The monitoring and prescription groups had higher values in all domains in the intragroup analysis. Physical function and health and mental health obtain the highest significant values between groups (p <.05). There are no significant differences at all in any domain among prescription and monitoring groups. However, the monitoring group obtained higher values in mental health, but were not in physical healt

    Performance of Rotational Grazing of \u3ci\u3eUrochloa\u3c/i\u3e Hybrid cv. Cayman in the Caribbean Region of Costa Rica

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    In Costa Rica pasture-based grass is the basis for both dairy and beef production. The Caribbean region with a rainfall exceeding 3000 mm has four seasons: dry (Feb-May), rainy (May-Aug), less rainy (Sep-Oct) and intermediate (Oct-Feb). Many pastures are dominated by Ischaemum ciliare (“Retana”), of poor nutritional quality and permanently grazed with low stocking rates (one animal per ha). To assess the potential of combining improved grasses with rotational grazing, a trial with Urochloa hybrid cv. Cayman was implemented at the INTA research station in Guápiles, Limón province, during four years (2014 to 2018). An intensive pasture management system based on the Voisin rational grazing methodology was applied in 21 paddocks of 0.2 ha, using 10-15 Brahman or Brahman x Simbrah steers, with 2.3 days of grazing and 46 days of pasture regrowth. For each year, the effect of growing season was determined on botanical composition, biomass production, intake and live weight gain. The botanical composition remained generally unchanged, with some encroachment of I. ciliare. Dry matter production increased during the first three years from 3.8 to 6.7 Mg, stabilizing in the fourth year; biomass availability was highest during the rainy season (6.6 Mg of DM/ha) and lowest during the dry season (4.2 Mg of DM/ha). Intake was 2.4% of live weight. Dry matter digestibility and crude protein content were 61% and 7% respectively. Average stocking rate was 2.4 Livestock Units (of 450 kg LW) per ha. The climatic seasons affected significantly LWG, which varied from 0.40 (intermediate season) to 0.82 (dry season) kg day-1 animal-1. Intensive rotational grazing with improved grass cv. Cayman lead to superior forage availability, stocking rates and LWG. However, very humid conditions reduce daily live weight gain by 50% and ways must be sought to improve animal wellbeing during the rainy periods

    Soil macroinvertebrates community and its temporal variation in a well-drained savannah of the Venezuelan Llanos

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    Morales-Márquez, Jimmy A., Hernández-Hernández, Rosa M., Sánchez, Gloria K., Lozano, Zenaida, Castro, Ignacio, Bravo, Carlos, Ramírez, Elizabeth and Jiménez Ballesta, Raimundo: "Soil macroinvertebrates community and its temporal variation in a well-drained savannah of the Venezuelan Llanos" published at European Journal of Soil Biology 84.2 (2018): 19-26; DOI: http://doi.org/10.1016/j.ejsobi.2017.11.002In the well-drained savannahs of Venezuelan Llanos, intensive agricultural activities could be causing damage to the soil, with negative consequences for the ecosystem. In order to avoid this problem, some agroecological alternatives are needed. Consequently, it is necessary to know the biologic dimension in this ecosystem, and within this, the soil macroinvertebrate community. The purpose of this work was to characterize this community in the natural savannah: its structure and diversity, its time variation and its relationship with the physical-chemical properties of the soil. A total of 72 samples were taken in different season along a period of time of 1405 days. The results revealed that the soil macrofauna had an average density of 243.5 ± 183.6 ind·m −2 , distributed in 32 families of 11 orders, with a diversity of N 1 = 4.5 ± 2.8 families. Coleoptera, Hymenoptera and Isoptera was the most dominants orders. The density, richness and diversity of families showed a temporal variation (r ≥ −0.5; p &lt; 0,05). Additionally, the structure of the soil macroinvertebrate community showed a vertical variation. The relationship with soil properties differed according families: Lampyridae, Aphodiidae and Formicidae had a positive correlation with soil macro-porosity (radius of the pores &gt; 15 μm); Tenthredinidae and Tenebrionidae had a positive correlation with the micro-porosity (pores ≤ 15 μm). The community in general, correlated positively with soil porosity and negatively with bulk density. This suggests that these soil properties need to be considered when designing agroecological technics in this area.We want to express our gratitude to the "Fondo Nacional para la Ciencia Innovación y Tecnología del Ministerio del Poder Popular para la Educación Universitaria, Ciencia y Tecnología", of the Boliviarian Republic of Venezuela, for the financial support of the project “Manejo Agroecológico de Suelos de Sabanas Bien Drenadas con Unidades de Producción Cereal-Ganado”, Nº G-2002000398, of which this study is part
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